Washer/dryer

ABSTRACT

The present invention relates to a washer/dryer ( 1 ), the drum of the washer/dryer ( 1 ) is rotated by an electric motor ( 2 ), and over heating of the electric motor ( 2 ) is controlled by a thermal protector ( 8 ) that cuts off the current passing through it when the detected temperature exceeds a predetermined limit value. The thermal protector ( 8 ) is energized by the triac ( 7 ) that drives the door lock ( 6 ) and thereby is prevented from being subjected to high currents.

The present invention relates to a washer/dryer comprising an electricmotor wherein a thermal protector is utilized against overheating.

In a household appliance, for example in a washing machine, thermalprotectors are utilized for the protection of electric motors againstoverheating and high currents that arise under conditions like thelocking of the rotor. The most preferred thermal protectors are thebimetal type comprising stationary and movable parts. The bimetalthermal protector functions like an electric switch, wherein thestationary part is in contact with the movable part during normaloperation of the electric motor, and when the electric motor isoverheated due to overloading, the movable part is deformed with theeffect of heat, losing contact with the stationary part and not allowingthe flow of electric current. The thermal protector can be situated onthe motor windings or anywhere the heat can be detected and is connectedin series to the motor windings to stop the operation of the electricmotor by cutting off the electricity in conditions of overheating and/orexcessive rise in the current.

In an electric motor driven by DC current, if the thermal protectorsensitive to high current and overheating is connected in series to thecircuit wherein the DC current flows, for example to the motor windings,it will malfunction in a short period of time and will not be able toserve since it will be subjected to continuous high current, thereforeit cannot be connected to the motor windings through which the DCcurrent flows.

In order to solve this problem, in a brushless DC electric motor ascited in the Great Britain Patent No GB2249441, the AC supply deliveredto the motor control circuit is changed to DC through a rectifier andthe thermal protector is connected in series to the AC voltage line butnot to the motor windings wherein the DC current flows.

The aim of the present invention is the realization of a washer/dryerwherein the thermal protector protecting the electric motor againstoverheating is prevented from damage through being affected by highcurrents.

The washer/dryer realized in order to attain the aim of the presentinvention is explicated in the claims.

In the washer/dryer, overheating of the electric motor actuating thedrum is controlled by a thermal protector and the thermal protector isprevented from being subjected to high currents and damaged by beingenergized with the triac that generates a low voltage which is also usedin energizing the washer/dryer door lock.

In an embodiment of the present invention, the thermal protectorterminals are connected in series at the triac outlet both to the doorlock and the relay control circuit, thereby not only halting the motorbut also turning off the energy delivered to the door lock when thethermal protector is opened.

In another embodiment of the present invention, the thermal protectorterminals are connected in series at the triac outlet only to the lineleading to the relay control circuit and halt only the motor withoutintervening with the door lock when the thermal protector is opened.

The washer/dryer realized in order to attain the aim of the presentinvention is illustrated in the attached figures, where:

FIG. 1—is the schematic view of a control circuit in a washer/dryer.

FIG. 2—is the schematic view of the control circuit in a washer/dryer inanother embodiment of the present invention.

The elements illustrated in the figures are numbered as follows:

-   -   1. Washer/dryer    -   2. Electric motor    -   3. Relay    -   4. Relay control circuit    -   5. Microprocessor    -   6. Door lock    -   7. Triac    -   8. Thermal protector

The washer/dryer (1) comprises an electric motor (2) that actuates thedrum wherein the laundry is emplaced, one or more relays (7) that isenergized with control signals received and changes to theactive-passive mode for actuating, halting or changing the operationaldirection of the electric motor (2), a relay control circuit (4) thatsends the signals which control the relay (3) and a microprocessor (5)that maintains the implementation and control of the washing program.

The washer/dryer (1) furthermore comprises a door for accessing the drumcontaining the laundry, a door lock (6), for example the bimetal type,that is locked when energized, and unlocked at the end of a delay periodwhen de-energized thereby allowing the door to be opened after the drumstops rotating with the effect of inertia, a triac (7) that activatesthe door lock (6) by operating the PTC (Positive TemperatureCoefficient) thermistor and a thermal protector (8) disposed in theelectric motor (2), that cuts off the current passing through it bybecoming open circuit when the temperature of the electric motor (2)exceeds a predetermined limit value.

A connection line (H1) is provided between the triac (7) and the doorlock (6) and the relay control circuit (4) is connected to theconnection line (H1) by means of a second connection line (H2) branchingfrom the said connection line (H1), the voltage generated by the triac(7) is delivered to the door lock (6) through the connection line (H1),and to the relay control circuit (4) through the connection line (H1)and the second connection line (H2).

The washer/dryer (1) of the present invention comprises a thermalprotector (8) connected in series between the triac (7) driving the doorlock (6) and the relay control circuit (4) and by being fed with the lowvoltage generated by the triac (7) is thus prevented from damage due tohigh currents.

During the normal operation of the electric motor (2) the thermalprotector (8) remains closed and allows the current to flow through it,not interrupting the transmission between the triac (7) and the relaycontrol circuit (4). The voltage generated by the triac (7) reaches therelay control circuit (4) and thereby actuates the relay control circuit(4), energizes the relay (3) and operates the electric motor (2). Whenthe temperature of the electric motor (2) exceeds the limit value, thethermal protector (8) opens, not allowing the current to flow throughit, interrupting the transmission between the triac (7) and the relaycontrol circuit (4) connected in series thereto and thus turns off thecurrent delivered to the relay control circuit (4) and hence the relay(3) and halts the electric motor (2). The thermal protector (8) not onlydetects the temperature of the electric motor (2) but also functions bybeing fed with the low voltage generated by the triac (7) without beingsubjected to high currents.

In an embodiment of the present invention, the thermal protector (8)terminals are connected to the connection line (H1) at the triac (7)outlet such that it can be connected in series both to the door lock (6)and the relay control circuit (4) (FIG. 1). When the thermal protector(8) opens at high temperature, the current delivered from the triac (7)both to the relay control circuit (4) and the door lock (6) is turnedoff. Thus the electric motor (2) is halted when the thermal protector(8) opens, and at the same time the door lock (6) is released since theenergy delivered to the door lock (6) is also interrupted and thelaundry can be unloaded by opening the door. The door lock (6) operatesby means of elements such as PTC thermistor and changes to the free modeto open the washer dryer (1) door, some time after being de-energized.In the delay period passing until the door lock (6) is released (forexample 90 seconds), the microprocessor (5) receiving the data from theconnection line (H1) that the thermal protector (8) has interrupted thecurrent flow in the circuit, sends the signal for discharging the waterin the tub and water is discharged in this delay period therebypreventing water from flowing outside when the door is opened.

In another embodiment of the present invention, the thermal protector(8) terminals are connected in series to the second connection line (H2)branching to the relay control circuit (4) from the connection line (H1)between the triac (7) and the door lock (6) such that it can beconnected in series only to the relay control circuit (4) at the triac(7) outlet (FIG. 2), and thus when the thermal protector (8) opens, onlythe energy delivered from the triac (7) to the relay control circuit (4)is turned off. When the thermal protector (8) opens, the energydelivered to the door lock (6) is not interrupted and the door is keptlocked. In this embodiment, the control of the door lock (6) is providedby the microprocessor (5) receiving data from the connection line (H1)and the second connection line (H2) that the thermal protector (8) isopened.

By means of the embodiment of the present invention, particularly inplaces wherein the voltage received from the main power supply isirregular, the thermal protector (8) is not fed by the AC voltage and bythe high DC voltage conveying lines feeding the electric motor (2), butinstead is fed by the voltage generated by the triac (7) actuating thedoor lock (6) and is not subjected to high currents and currentfluctuations, hence damage is prevented and a longer service life isprovided.

1. A washer/dryer (1) comprising an electric motor (2) that actuates thedrum wherein the laundry is emplaced, one or more relays (7) that isenergized with the control signals received and changes to theactive-passive mode for actuating, halting or changing the operationaldirection of the electric motor (2), a relay control circuit (4) thatsends the signals which control the relay (3) and a microprocessor (5)that maintains the implementation and control of the washing program, adoor lock (6) that is locked when energized, and unlocked at the end ofa delay period when de-energized, a triac (7) that actuates the doorlock (6) and a thermal protector (8) disposed in the electric motor (2)that cuts off the current passing through it, by becoming open circuitwhen the temperature of the electric motor (2) exceeds a predeterminedlimit value, characterized by the thermal protector (8) connected inseries between the triac (7) driving the door lock (6) and the relaycontrol circuit (4) and by being fed with the low voltage generated bythe triac (7) is thus prevented from damage due to high currents.
 2. Awasher/dryer (1) as in claim 1, characterized by a connection line (H1)provided between the triac (7) and the door lock (6), and the relaycontrol circuit (4) that is connected to the connection line (H1) by asecond connection line (H2) branching from the said connection line(H1).
 3. A washer/dryer (1) as in claim 2, characterized by the thermalprotector (8), the terminals of which are connected to the connectionline (H1) such that it is connected in series both to the door lock (6)and the relay control circuit (4) at the triac (7) outlet.
 4. Awasher/dryer (1) as in claim 3, characterized by the microprocessor (5)that receives data from the connection line (H1) connected thereto thatthe thermal protector (8) has interrupted the circuit, and when the doorlock (6) is de-energized, sends the signal for discharging the water inthe tub during the delay period until the door opens.
 5. A washer/dryer(1) as in claim 2, characterized by a thermal protector (8), theterminals of which are connected to the second connection line (H2)branching to the relay control circuit (4) from the connection line (H1)between the triac (7) and the door lock (6) such that it can beconnected in series only to the relay control circuit (4) at the triac(7) outlet.
 6. A washer/dryer (1) as in claim 5, characterized by amicroprocessor (5) that controls the door lock (6) by receiving datafrom the connection line (H1) and the second connection line (H2) thatthe thermal protector (8) is opened.